In 1492 a Spanish transatlantic maritime expedition led by Christopher Columbus led to the already populated continents of the Americas, previously unknown in Europe. Columbus and his crew became the first Christian Europeans to make landfall in the Americas. Columbus was an Italian navigator sailing for the Spanish Crown. He sought a westward route to Asia, which led to the discovery of a New World. Over four voyages to the Americas between 1492 and 1498, Columbus set the stage for the European exploration and colonization of the Americas, ultimately leading to the Columbian Exchange. Considered an indicator of the start of Modern history, the great significance of his voyages to the History of the world is uncontested.